1. Field of the Invention
The present invention generally relates to an electronic endoscope apparatus. More specifically, the present invention is directed to an improved objective lens system employed in a non-bending distal end portion of an electronic endoscope apparatus.
2. Description of the Related Art
In a conventional electronic endoscope apparatus equipped with an electronic (endoscopic) scope having an objective optical system mounted on a non-bending distal end portion thereof, a focusing mechanism is directly screwed to this distal end portion and then fixed therein.
With such a focusing mechanism screwed to the non-bending distal end portion, there are drawbacks. The simple assembling of the distal end portion of the conventional electronic scope may not be as easy as first expected, and secondly the focusing thereof may be difficult. Furthermore, amount of projection of the objective (endoscope) lens beyond the distal end of the endoscope body can vary, depending upon the manufacturing conditions of the conventional electronic endoscope apparatuses, i.e., the fine adjustment states of the focusing.
If the surface projection amounts of the objective optical systems become irregular for each electronic scope, the cleaning fluid break of the scope cannot always be expected when the endoscopic examination is interrupted or completed and, then the electronic scope is cleaned with cleaning fluid.
The present invention has been made to solve the above-explained problems with a conventional electronic endoscope apparatus and, therefore, has as an object to provide an electronic endoscope apparatus equipped with an electronic scope on which such an objective optical system with easy focusing is mounted with easy assembling, whereby surface projection amounts of the objective lens do not become irregular every time during objective focusing.